library(plotly)
fxyval<-function(x,y){cos(sqrt(x^2+y^2))}
fxyval2<-function(x,y){x^2/12+y^2/12+1.2}

x<-seq(-10,10,by=0.1);y<-x
z<-outer(X = x,Y = y,FUN = fxyval) %>% t()
z2<-outer(X = x,Y = y,FUN = fxyval2) %>% t()

plot_ly( x = ~x,y = ~y,z = ~z,type = 'surface',showscale = FALSE)%>%
  layout(title = 'Grafica f(x,y)',scene=list(
        xaxis=list(title="eje x",color="blue"),
        yaxis=list(title="eje y",color="green"),
        zaxis=list(title="eje z",color="orange")))%>%
  add_surface(z = ~z2)